1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * reservations.h 4 * 5 * Allocation reservations function prototypes and structures. 6 * 7 * Copyright (C) 2010 Novell. All rights reserved. 8 */ 9 10 #ifndef OCFS2_RESERVATIONS_H 11 #define OCFS2_RESERVATIONS_H 12 13 #include <linux/rbtree.h> 14 15 #define OCFS2_DEFAULT_RESV_LEVEL 2 16 #define OCFS2_MAX_RESV_LEVEL 9 17 #define OCFS2_MIN_RESV_LEVEL 0 18 19 struct ocfs2_alloc_reservation { 20 struct rb_node r_node; 21 22 unsigned int r_start; /* Beginning of current window */ 23 unsigned int r_len; /* Length of the window */ 24 25 unsigned int r_last_len; /* Length of most recent alloc */ 26 unsigned int r_last_start; /* Start of most recent alloc */ 27 struct list_head r_lru; /* LRU list head */ 28 29 unsigned int r_flags; 30 }; 31 32 #define OCFS2_RESV_FLAG_INUSE 0x01 /* Set when r_node is part of a btree */ 33 #define OCFS2_RESV_FLAG_TMP 0x02 /* Temporary reservation, will be 34 * destroyed immedately after use */ 35 #define OCFS2_RESV_FLAG_DIR 0x04 /* Reservation is for an unindexed 36 * directory btree */ 37 38 struct ocfs2_reservation_map { 39 struct rb_root m_reservations; 40 char *m_disk_bitmap; 41 42 struct ocfs2_super *m_osb; 43 44 /* The following are not initialized to meaningful values until a disk 45 * bitmap is provided. */ 46 u32 m_bitmap_len; /* Number of valid 47 * bits available */ 48 49 struct list_head m_lru; /* LRU of reservations 50 * structures. */ 51 52 }; 53 54 void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv); 55 56 #define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP|OCFS2_RESV_FLAG_DIR) 57 void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv, 58 unsigned int flags); 59 60 int ocfs2_dir_resv_allowed(struct ocfs2_super *osb); 61 62 /** 63 * ocfs2_resv_discard() - truncate a reservation 64 * @resmap: 65 * @resv: the reservation to truncate. 66 * 67 * After this function is called, the reservation will be empty, and 68 * unlinked from the rbtree. 69 */ 70 void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap, 71 struct ocfs2_alloc_reservation *resv); 72 73 74 /** 75 * ocfs2_resmap_init() - Initialize fields of a reservations bitmap 76 * @resmap: struct ocfs2_reservation_map to initialize 77 * @obj: unused for now 78 * @ops: unused for now 79 * @max_bitmap_bytes: Maximum size of the bitmap (typically blocksize) 80 * 81 * Only possible return value other than '0' is -ENOMEM for failure to 82 * allocation mirror bitmap. 83 */ 84 int ocfs2_resmap_init(struct ocfs2_super *osb, 85 struct ocfs2_reservation_map *resmap); 86 87 /** 88 * ocfs2_resmap_restart() - "restart" a reservation bitmap 89 * @resmap: reservations bitmap 90 * @clen: Number of valid bits in the bitmap 91 * @disk_bitmap: the disk bitmap this resmap should refer to. 92 * 93 * Re-initialize the parameters of a reservation bitmap. This is 94 * useful for local alloc window slides. 95 * 96 * This function will call ocfs2_trunc_resv against all existing 97 * reservations. A future version will recalculate existing 98 * reservations based on the new bitmap. 99 */ 100 void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap, 101 unsigned int clen, char *disk_bitmap); 102 103 /** 104 * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure 105 * @resmap: the struct ocfs2_reservation_map to uninitialize 106 */ 107 void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap); 108 109 /** 110 * ocfs2_resmap_resv_bits() - Return still-valid reservation bits 111 * @resmap: reservations bitmap 112 * @resv: reservation to base search from 113 * @cstart: start of proposed allocation 114 * @clen: length (in clusters) of proposed allocation 115 * 116 * Using the reservation data from resv, this function will compare 117 * resmap and resmap->m_disk_bitmap to determine what part (if any) of 118 * the reservation window is still clear to use. If resv is empty, 119 * this function will try to allocate a window for it. 120 * 121 * On success, zero is returned and the valid allocation area is set in cstart 122 * and clen. 123 * 124 * Returns -ENOSPC if reservations are disabled. 125 */ 126 int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap, 127 struct ocfs2_alloc_reservation *resv, 128 int *cstart, int *clen); 129 130 /** 131 * ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used. 132 * @resmap: reservations bitmap 133 * @resv: optional reservation to recalulate based on new bitmap 134 * @cstart: start of allocation in clusters 135 * @clen: end of allocation in clusters. 136 * 137 * Tell the reservation code that bits were used to fulfill allocation in 138 * resmap. The bits don't have to have been part of any existing 139 * reservation. But we must always call this function when bits are claimed. 140 * Internally, the reservations code will use this information to mark the 141 * reservations bitmap. If resv is passed, it's next allocation window will be 142 * calculated. It also expects that 'cstart' is the same as we passed back 143 * from ocfs2_resmap_resv_bits(). 144 */ 145 void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap, 146 struct ocfs2_alloc_reservation *resv, 147 u32 cstart, u32 clen); 148 149 #endif /* OCFS2_RESERVATIONS_H */ 150